In appendiceal tumors, KRAS gene mutations are identified in more than 50% of cases [13], being present in some cases of epithelial tumors: sessile serrated lesions with or without dysplasia [15,16,21,22,23], low-grade appendiceal mucinous neoplasm (LAMN) [7,8,9,24,25,26,27,28,29,30,31,32,33,34], high-grade appendiceal mucinous neoplasms (HAMN) [27,29], mucinous adenocarcinomas of the appendix [12,35], non-mucinous adenocarcinomas of the appendix [35], and appendiceal goblet cell adenocarcinoma [36,37], but is completely lacking in neuroendocrine tumors of the appendix (Figure 3). Here, KRAS is linked to mucinous adenocarcinoma of the appendix.